Effects of high hydrostatic pressure on chlorophylls and chlorophyll-protein complexes in spinach

摘要

Chlorophylls and chlorophyll-protein complexes determine the color and other sensory properties of spinach. This study investigated the effects of high hydrostatic pressure (HHP) (100, 250, and 500 MPa for 5 min) treatments on structure, chlorophylls and soluble protein contents, protein peptide and fatty acid compositions, chlorophylls absorption spectra, emission, and excitation fluorescence spectra of thylakoid membrane in spinach, in order to better understand the changes in chlorophylls and chlorophyll-protein complexes under HHP. The result showed that HHP-treated samples showed a compact and stacked structure of thylakoid membrane in spinach. For the components of thylakoid membrane, both of chlorophylls and soluble protein contents were significantly (p 0.05) reserved by HHP treatments. The composition of proteins, peptides, and fatty acids was close to untreated samples, revealing higher stability under HHP. In addition, chlorophylls emission and excitation fluorescence spectra capacities of thylakoid membrane were better maintained under HHP treatments compared with thermal treatment, indicating higher light-harvesting and excitation efficiencies of Photosystem II (PS II). As the key functional component of thylakoid membrane, retention of PS II reflected the stability of thylakoid membrane functions under HHP. Hence, chlorophylls and chlorophyll-protein complexes were effectively sustained under HHP treatments, providing new opportunities to preserve the color quality of green vegetables.